BMW M4 Competition v Mercedes-AMG C63 S Coupe road comparison

The choice between the BMW M4 and Mercedes-AMG C63 S Coupe is an extremely difficult one. Not because both cars are excellent overall, but because they are so different.

Having previously compared the M3 against the C 63 S sedan, the reason for this two-door comparison was rather simple. The difference between the C63 S sedan and coupe is rather massive, both in terms of its suspension set-up and its general offering. Meanwhile, the M4 performance takes the level of hardcore from the Bavarian brand yet another step forward.

This comparison is broken up in to two parts, the first of which is the road test, followed next month by the track test. Usually we would conduct the road test and then ask a pro driver to do the track times, this time though, we decided to do it differently.

To get a better perspective, we asked Australia’s most successful rally driver, former WRC driver and current RallyCross hero Chris ‘Atko’ Atkinson, to join us for the road test. The reason for this is Atko has an invaluable amount of knowledge about car set-up and gives the type of feedback about performance cars that we simply wouldn’t have without years of professional racing experience.

So, here are the two cars:

The BMW M4 Competition coupe ($154,615), loaded with $2740 worth of options to bring the price up to $157,355.

Its rival in this comparison is the Mercedes-AMG C 63 S Coupe ($162,115), equipped with the AMG Carbon Fibre trim pack ($1490), for a total price of $163,605.

That’s a $6250 difference in favour of the Beemer, and at this price range, not all that material.

The M4 has a 7-speed M double-clutch transmission coupled to its six-cylinder 3.0-litre twin-turbo engine with 331kW of power and 550Nm of torque. BMW claims a 0-100km/h time of 4.0 seconds.

The C 63 S Coupe uses a conventional seven-speed transmission taking control of the mighty 4.0-litre twin-turbo V8 with 375kW of power and 700Nm of torque. Its official 0-100km/h time is 3.9 seconds.

So both these cars are insanely quick, there’s no question there, and despite the power and torque differences, the M4 makes up for its deficit with a roughly 230kg weight advantage. In fact, interestingly, the C63 coupe weighs 70kg more than the sedan!

According to Mercedes-Benz that’s due to the vehicle being wider, having bigger wheels and a completely different suspension set-up (along with further structural rigidity).

Somehow having two fewer doors didn’t seem to do all that much for the weight. Also, because of the wider track and better traction, 0-100km/h is 0.1 of second faster in the coupe!

So, first of all, a loop around inner Brisbane CBD on the way to Mounts Glorious and Nebo. In comfort mode the C63 is ultra-plush, it almost hovers over bumps and the huge amounts of torque means it can putt around in high gear and still get around effortlessly.

That’s not the case in the M4. With the competition pack (and even without) the ride is noticeably firmer. Not necessarily harsher, but firmer. It just passes more of the road surface into the cabin and if you frequent bad roads, this can get annoying after a while.

As for the interior both cars are very luxurious with the latest in safety and infotainment technology. There is room in the back for two adults if the need ever arises, but it would be for short trips unless they measure below 165cm.

Around town both Germans are easy to drive and manoeuver, with enough sensors and cameras to shame an Airbus - making parking and getting through tight spaces a non-issue. Even so, the M4 wheels do tend to poke out a bit, so that is worth considering if you do a lot of kerb-side parking.

As a daily driver and in terms of which car we would like to be stuck in traffic with, it was a clear win for the Mercedes-AMG for it provided the most comfortable cabin, even though its COMAND infotainment system really lacks the polish and ease of use of BMW’s iDrive.

Nor is the head-up display as good as the Beemer’s, but the win for ride comfort and the overall driving experience in traffic and around suburbia goes to the men and women in Affalterbach.

With that sorted, we ventured up the glorious mountain range that exists just a few minutes' drive from Brisbane’s ever expanding CBD.

Here, where the roads are twisty and the legal speed limit still high enough to have fun around bends, yours truly sat next to Atko to hear his thoughts on each car’s character.

Firstly, he is a big fan of the torque from the C63’s V8, as you can see in his review of the sedan here, and initially there was a lot of praise from him in that regard, and both of us agreed that on the go the sound of the AMG is mind-blowingly good. Listen to both cars here on our Facebook page.

But as we progressed further up the mountain and swapped around between the Germans, Atko's preference changed quickly.

The C63 S Coupe, Atko says, is not as stable dynamically and much lighter in the rear under braking. Meanwhile, being able to position the car exactly where it needs to be is much easier in the M than the AMG.

Additionally, the high torque results in minimal rear traction and due to the car’s suspension being naturally softer, it does tend to bottom out the dampers on the odd occasion.

On the plus side, the C63 possesses more predictable and controlled oversteer while Atko agreed with our assessment that it’s the easier of the two cars to drive faster without much work. He notes that the best way to drive it fast is to accept the understeer (caused by the weight transfer to the front under heavy braking) and square it off with oversteer on the throttle. Not something we were all that keen to experiment with, if we are honest.

From our perspective, the C63 rolled around the bends far more evidently than the M4. Yet, given the huge amount of pull from down low in the rev range, it allowed the car to get back up to speed much quicker than its rival - meaning it was easier to drive fast for a novice. The Bavarian offering was much tighter in the corners - and certainly felt like it had endless grip - but required you to be up it at all times to extract the same level of performance the AMG provided as part of its natural existence.

Further, the M4 felt nervous, as if it had limitless grip, until it didn’t. There was far less sense of progression to that limit than in the AMG, at least for us. Atko didn’t think that was as much of an issue.

What Atko praised heavily on the M4 was the way it behaved under braking, not diving – as per the Mercedes – and being extremely well-planted under extreme braking situations, allowing for far better entry into corners (further helped by its stiffer suspension and lighter weight).

The M4’s steering was also very well-liked by both parties, with Atko noting that it felt far more precise than the M3 Competition we tested recently.

But perhaps most annoying for all of us, was the amount of road noise evident in the BMW when pushed, while the Mercedes was super quiet inside despite being punted equally as hard.

Dynamically then, the BMW had the Mercedes-AMG covered with ease and despite the oversteery fun one can have with the AMG, we both agreed that if mountain runs were a frequent part of the ownership experience, the M4 would be the pick of the two.

So we said our goodbyes, decided the BMW had the edge in this comparison despite its shortcomings and went our own ways. Atko took the M4 and we took the C63 S.

A few days passed and we touched base to gather our thoughts and decide a winner. And, without having actually exchanged any words in the meantime, we had both changed our minds in the AMG’s favour.

“Not sure I would want to live with the M4 everyday,” was the common consensus. Yes, it’s very good as a sports car, but as a car you want to drive day-in day-out? Not so much.

In that case, then, for us the road comparison is a win for the Mercedes-AMG, just.

Not because the M4 is inferior, but because it’s almost too hardcore, it’s almost too good to be wasted in traffic. Also because the AMG’s humongous torque allows it to be enjoyed more lazily even in comfort mode, while you really have to press all of the BMW's switches into M to get it into the right mode and then get up high in the rev range to get the most from the six-cylinder unit.

Out on the track though, we suspect it will be a different story.

We will find out which reigns supreme when Atko puts both cars on track early next month.

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